Bone graft delivery system and method

ABSTRACT

A surgical technique for the delivery of bone graft to a medullary canal and implantation of a prosthetic device includes placing bone graft into an elongate hollow tube and arranging a plunger having an elongate rod portion into the hollow tube. The hollow tube, bone graft and plunger assembly are inserted into the medullary canal which has been prepared for the assembly by reaming the medullary canal with a reamer corresponding in size to the hollow tube. The hollow tube is withdrawn from the medullary canal while the plunger is pushed into the canal, resulting in bone graft exiting the hollow tube and being packed by the plunger. A trial prosthesis is used to shape the bone graft within the canal for the prosthesis. Space for a cement mantle can be left through the use of an appropriately sized trial prosthesis.

BACKGROUND OF THE INVENTION

The present invention relates generally to a method of surgicallyimplanting a new prosthesis at a joint, and more specifically toinstruments and techniques for efficiently using bone graft tofacilitate the implantation of a prosthesis.

It is known to use bone graft to prepare a seat for a prosthesis, eitherwith or without a cement mantle. A bone grafting procedure is often usedwhere there is an appreciable loss of strong bone stock, as is often thecase in revision surgery (in which a previously implanted prosthesis isreplaced with a new prosthesis). The seat prepared with bone graft maybe made up entirely of bone graft to substantially surround aprosthesis, or the seat may be made up of bone graft and the naturalbone at the implantation site (for instance, where bone graft is used tofill a relatively small void in the natural bone where the bone isotherwise intact). Bone graft typically includes crushed bone(cancellous and cortical), or a combination of these (and/or othernatural materials) and synthetic biocompatible materials. Bone graft ofthis type is intended to stimulate growth of healthy bone. As usedherein, "bone graft" shall mean materials made up entirely of naturalmaterials, entirely of synthetic biocompatible materials, or anycombination of these materials.

U.S. Pat. No. 5,015,256 to Bruce discloses a surgical technique by whichthe medullary canal is reamed and filled with bone graft, the bone graftbeing compacted by driving the stem of the prosthesis into the medullarycanal. Also, U.S. Pat. No. 4,800,875 to Ray discloses a method ofinserting bone graft into a bone and tamping the bone graft. EuropeanPatent Publication No. 0 179 626 A2 discloses the use of bone graft toenhance implant/bone contact, whereby the stem of a hip implant isintended to subside within an implant sleeve. Also, an article entitled"Histology of cancellous Impaction Grafting In The Femur," by Ling etal., Journal of Bone and Joint Surgery Br!, Vol. 75-B, No. 5, September1993, reports a 1988 revision of a hip implant in which allograft chipswere impacted within the medullary canal with an oversized stem,followed by use of cement and implantation of a polished-surface stem.In addition, Complications Of Total Hip Arthoplasty, by Richard H.Rothman and William J. Hozack, W. B. Saunders Co., 1988, teaches atechnique of bone grafting in the femoral canal in a revision surgery,using uncemented components.

Of course, it is desirable to properly prepare the medullary canaladjacent a joint for receiving bone graft so that a prosthesis can beproperly positioned during implantation. Thus, the preparation of themedullary canal and the positioning of the prosthesis or trialprosthesis in the prepared medullary canal are often critical steps inproperly implanting a prosthesis. To this end, rasps having aconfiguration similar to the prosthesis are well-known, as shown, forexample, in U.S. Pat. No. 3,874,003 to Moser (FIG. 8), U.S. Pat. No.4,306,550 to Forte and U.S. Pat. No. 4,552,136 to Kenna. These devicesfacilitate the proper shaping of the femoral medullary canal in aconfiguration which is similar to their respective hip prostheses ortrial hip prostheses.

Centering devices (rods and guidewires) are also known for controllingthe machining or other preparation of the medullary canal, as well asfor centering a trial prosthesis during trial reduction or centering aprosthesis during implantation. U.S. Pat. No. 4,91,673 to Willert, U.S.Pat. No. 4,994,085 to Sawai and U.S. Pat. No. 5,078,746 to Garner eachdisclose the use of centering rods in the distal femoral canal to centerhip joint prostheses and/or trial hip joint prostheses during trialreduction and final implantation. The hip joint prostheses and trial hipjoint prostheses each have longitudinal passageways which receive thecentering rods or guidewires already in the canal. Centering rods orguidewires are also used in connection with machining and shapinginstruments so that the preparation of the canal is controlled about thecentering rod or guidewire and so that the preparation is consistentfrom instrument to instrument. U.S. Pat. No. 4,341,206 to Perrett, U.S.Pat. No. 4,751,922 to DiPietropolo, U.S. Pat. No. 5,192,283 to Ling,U.S. Pat. No. 5,122,134 to Borzone and U.S. Pat. No. 5,190,548 to Davisdisclose cannulated reamers and drills which are used with centeringrods or guidewires for centering or positioning the shaping tools duringpreparation of a medullary canal or bone.

U.S. Pat. No. 5,192,283 to Ling also discloses the use of a trial hipprosthesis having a longitudinal passageway for receiving the veryguidewire which facilitated the reaming and rasping of the canal. Bonegraft is inserted into the canal around the guidewire, and thecannulated trial prosthesis is used to simultaneously compact and formor shape a prosthesis-receiving cavity larger than and similar in shapeto the new prosthesis. Bone graft is continuously placed into the canalduring the use of the cannulated trial prosthesis in order to build upthe bone graft in the canal. A series of successively larger cannulatedtrial prostheses could be used to compact the bone graft.

The technique described in Ling is a somewhat time-consuming surgicalprocedure. Factors which add to the time-consuming nature of thistechnique include the steps which must be repeated to complete theinsertion of bone graft into the canal and the requirement that allsteps take place in the medullary canal. In addition, the techniquedescribed in Ling relies on a guidewire which could shift duringpreparation of the canal.

The present invention provides an easily implemented and efficienttechnique for the delivery of bone graft to a medullary canal orelsewhere in the body. One embodiment relates specifically to bonegrafting within the medullary canal adjacent a joint to prepare thecanal for receiving a prosthesis.

SUMMARY OF THE INVENTION

The present invention is directed to the delivery of bone graftmaterials to any area of the body and in particular to the medullarycanal of any bone. The invention can be used in the repair of a bone orin connection with the implantation of prosthetic devices at any bone inthe body, including without limitation the hip, knee and spinal joints.Further, the present invention can be used in primary surgery, in whicha prosthesis is being used to reconstruct a joint for the first time, aswell as in revision surgery, in which a previously-implanted prosthesisis being replaced with another prosthesis. Press fit, cement or otherfixation techniques can be employed in conjunction with the presentinvention. The technique in accordance with the present invention issuitable for the delivery of bone graft into the medullary canal tofully or partially line the medullary canal.

It is an object of the present invention to provide a bone graftdelivery system for delivering bone graft, in a partially formed, fullyformed or unformed condition to a graft receiving area in a body. Thegraft receiving area can be any area, but is often the medullary canalof a bone. In the preferred embodiment, the bone graft is delivered in apartially formed manner, and in accordance with another aspect of thepresent invention, requires further formation after initial delivery ofthe bone graft.

It is another object of the present invention to provide a method andapparatus by which a hollow tube and a plunger associated with thehollow tube are provided to facilitate delivery of the bone graft to abone graft receiving area. In the preferred embodiment, positioningstructure is provided on the plunger to maintain the plunger in adesirable position with respect to the hollow tube. Adjunct positioningmeans may also be provided to ensure that the plunger remains in thedesirable position during the packing of bone graft into the hollowtube.

It is another object of the present invention to provide a method andapparatus by which a plunger and hollow tube assembly can be packed withbone graft, and then together inserted into the medullary canal oradjacent to another bone graft receiving area. Subsequently, the hollowtube can be withdrawn to leave the plunger in place in order to form inthe bone graft a cavity in the shape of the plunger. In the preferredembodiment, the plunger can then be removed, and a series ofsequentially larger trials can be used to shape the bone graft withinthe medullary canal.

It is another object of the present invention to provide a bone graftdelivery system, by which bone graft can be selectively and controllablydelivered to a specific area. For instance, bone graft may be deliveredto one portion of the wall in the medullary canal, as opposed all of thewalls in the medullary canal.

It is another object of the present invention to provide a hollow tubeand plunger assembly, in which the hollow tube is disposable.

It is another object of the present invention to provide a bone graftdelivery system, by which a hollow tube and possibly a hollowtube/plunger assembly can be prepared prior to even opening a patient,thus minimizing the overall impact of the grafting aspect of a surgicalimplantation or other procedure.

The present invention can be carried out by a method in which access isprovided to a graft receiving area in a body, bone graft is placed intoa hollow tube having a first end and a second end, the hollow tube,together with the bone graft, is arranged so that the first end of thehollow tube is at least adjacent to the graft receiving area, and thehollow tube is moved away from the graft receiving area, in a directionfrom the first end to the second end of the hollow tube, such that thebone graft exits the first end of the hollow tube and remains at thegraft receiving area. A graft retaining structure may also be providedto block an end of the hollow tube, so as to facilitate the exit of thebone graft from the hollow tube. The graft retaining structure may alsobe used in such a way that it is maintained in one position while thetube is moved away from the graft receiving area. Alternatively, thegraft retaining structure can be used by forcing it toward the graftreceiving area, while the hollow tube is being moved away from the graftreceiving area.

The present invention may also be carried out by exposing the medullarycanal of a bone, placing bone graft into a hollow tube having a firstend and a second end, inserting the first end of the hollow tube intothe medullary canal, and withdrawing the hollow tube from the medullarycanal, such that bone graft exits the first end of the hollow tube intothe medullary canal. Again, the bone graft can be forced from the hollowtube by blocking an end of the hollow tube. The above technique may alsoinclude arranging a plunger having an elongate rod portion at leastpartially in the hollow tube and removing the plunger from the medullarycanal to leave a cavity formed at least partially in the bone graft. Thehollow tube can be inserted into the medullary canal together with theplunger and bone graft, and upon withdrawal of the hollow tube from themedullary canal, the plunger remains at least partially in the canal.Pressure can be applied to the plunger during withdrawal of the hollowtube to at least maintain the plunger at least partially in themedullary canal. Further pressure may also be applied to the plunger toforce the plunger further into the medullary canal, either whilewithdrawing the hollow tube from the medullary canal or subsequent tothe withdrawal of the hollow tube, whereby the bone graft deposited inthe medullary canal would be further packed by the plunger.

The bone graft deposited in the medullary canal by the tube/plungerassembly can be shaped, if not already shaped, with a prosthesis or atrial prosthesis having a configuration similar to the prosthesis to beimplanted. The bone graft material in the medullary canal can becompacted with successively larger trial prostheses to progressivelyshape the bone graft. If the prosthesis to be implanted is to becemented in place in the canal, the final trial prosthesis used to shapethe bone graft can be of a size larger than the prosthesis to beimplanted, so as to leave a cement mantle.

The plunger used in connection with the hollow tube can be modular innature, such that different portions of the plunger can be matchedaccording to preoperative or intraoperative indications. Also, anypositioning devices or graft retaining structures used in connectionwith the plunger can also be modular and selectable from a group ofdifferent devices to fit the particular application and hollow tube.

The present invention may also be carried out by providing a hollow tubehaving a first end and a second end, and being constructed so that itcan receive bone graft, and so that the first end can be arranged atleast adjacent to a bone graft receiving area, and so that bone graftcan be delivered from the first end of the hollow tube to the bone graftreceiving area upon movement of the hollow tube in a direction from thefirst end to the second end. A graft retaining structure can also beprovided for use in connection with the hollow tube, as can a graftpacker. In addition, a plunger can be provided with the hollow tube.

Another aspect of the present invention can be carried out by providingan extractor to facilitate the controlled movement of a tube whichsurrounds a rod, while leaving the rod substantially in position, theextractor including a housing, a connector for connecting the housing tothe tube, a stem movable within the housing for applying pressure to arod in its arranged position, and actuating means for applying pressureto such a rod. The stem may have a rod-engaging portion sized to engagea rod in a tube and to permit the tube to be withdrawn from around therod so that the tube is disposed around the stem. The extractor isconstructed and arranged so that upon actuation thereof, the stemapplies pressure against the rod, and the housing, with a connectedtube, is moved away from the arranged position, while leaving the rod inthe arranged position.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects of the present invention will becomeapparent, as will a better understanding of the concepts underlying thepresent invention, by reference to the description which follows andrefers to the accompanying drawings in which:

FIG. 1 is an elevational view of a hollow intramedullary tube and anassociated extraction cap in accordance with an embodiment of thepresent invention;

FIG. 2 is an elevational view of a plunger rod in accordance with anembodiment of the present invention;

FIG. 3 is an elevational view of a modular plunger rod and associatedmodular centering devices, in accordance with another embodiment of thepresent invention;

FIG. 4 is an elevational view of a hollow bone graft packer inaccordance with the present invention;

FIG. 5 is an elevational view of a plunger rod assembled within a hollowintramedullary tube (with extraction cap), illustrating in particularthe packing of the tube/plunger assembly with bone graft through the useof a hollow bone graft packer;

FIGS. 6A-6F are elevational views, in partial cross-section of animplant technique in accordance with the present invention, illustratingin particular the delivery of bone graft to the proximal femoralmedullary canal and the formation of the implant-receiving cavity withinthe graft-lined medullary canal;

FIG. 7A is a top plan view of a tube extractor (a modified cementinjector) in accordance with the present invention;

FIG. 7B is an elevation view in partial cross-section of the bone graftdelivery technique in accordance with the present invention,illustrating in particular the use of a tube extractor (associated withthe extraction cap) to remove the hollow intramedullary tube from themedullary canal while leaving the plunger rod with the packed bone graftin place;

FIG. 8 is an elevational view of a plunger rod assembled within a hollowintramedullary tube, illustrating in particular adjunct centering meansin the form of diametrically opposed centralizing screws;

FIG. 9 is an elevational view of a plunger rod assembled within a hollowintramedullary tube, illustrating in particular adjunct centering meansin the form of a slideable centralizing washer held on the rod by aninterference fit; and

FIG. 10 is an elevational view, in partial cross-section, showing theselective delivery of bone graft to a specific area of the medullarycanal through the use of a specifically structured plunger rod.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-4 illustrate some of the instruments which may be used tofacilitate the delivery of bone graft in accordance with the presentinvention. The instruments illustrated are for the delivery of bonegraft to the femoral medullary canal, but the concepts underlying thepresent surgical technique may be applied to the delivery of bone graftto the medullary canal of any bone, adjacent to or remote from anyjoint.

FIG. 1 shows a hollow intramedullary tube 10 and an extraction cap 12 inaccordance with the present invention. The tube is preferably hollowfrom one end to the other, but may be partially hollow depending uponthe application and structure of the instruments used with it. (The word"hollow" will thus be used in this sense.) The tube 10 is preferablymade of metal and preferably includes a thin-wall 10A (see FIG. 5) in atleast the portion which will be inserted into a medullary canal. Thetube 10 includes a tube flange 14 and male threads adapted to receivethe female threads of the extraction cap 12 (see FIG. 5). The extractioncap 12 includes a groove 16 and retaining flange 18 for cooperation withthe slotted retaining sleeve of a tube extractor (to be discussed laterin connection with FIGS. 7A and 7B). The extraction cap 12 can be madeof any suitable material, such as plastic or metal.

The hollow tube 10 and extraction cup 12 may also be made of adisposable material, such as a disposable plastic, so that theseinstruments can be disposed of after they are used once. If made of adisposable material, the extractor cap 12 can be made integrally withthe hollow tube 10. Moreover, the hollow tube 10 can be made to bestored with bone graft in it for a period of time, whether the tube 10is made of plastic, metal or any other material. In this regard,depending upon the surgical application, it may be desirable to onlypartially fill the tube for storage or at least not pack it tightly, sothat a plunger can be inserted at the time of a surgery. The tube mayalso be made of a biocompatible material which can stay in the canalwithout impairing the final implantation. Alternatively, it may thus bea material that is resorbable, such as a resorbable polymer, in thecanal after implantation, so as not to interfere with the growth of thebone or stability of the implant.

The hollow tube 10 can be of any suitable shape for insertion into themedullary canal of a bone (or any other area of the body) depending uponthe application, but is preferably cylindrical in shape. In this regard,as used herein, "tube" shall be construed broadly to encompassstructures of any suitable shape for retaining graft material prior todelivery to a medullary canal or any other area of the body. The tube 10is preferably made in several different diameters, for example 16 mm, 18mm, 20 mm and 22 mm. The selection of the appropriate tube 10 willdepend upon preoperative and intraoperative indications. In this regard,the extraction cap 12 is preferably a "universal" extraction cap in thesense that only one extraction cap will be needed for an entire set ofdifferently sized hollow intramedullary tubes. Thus, an instrument kitfor a particular joint might include several differently-sized hollowintramedullary tubes to accommodate surgical needs.

As will be discussed in more detail below, reamers may be used to cleanmaterial (e.g., residual cement from previous implant, marrow,cancellous or cortical bone) out of the medullary canal prior to theinsertion of the tube 10. An instrument kit might thus include a set ofreamers corresponding in size to the hollow intramedullary tubes in thatinstrument kit. Once a medullary canal has been prepared with theappropriately sized reamer, the corresponding tube will properly fit inthe canal.

FIG. 2 shows a plunger of an elongate construction having a centralizingcap or flange 22 at one end (the proximal end) and a centralizing collar24. The centralizing cap 22 and the centralizing collar 24 are presentto position--in this case, center--the plunger 20 within the tube 10. Atleast the centralizing collar 24 also serves a graft retaining functionduring the delivery of the bone graft to the medullary canal. Thisensures that the bone graft is not withdrawn from the medullary canal asthe tube 10 is being withdrawn from the canal. This may occur bymaintaining the collar 24 in one position while withdrawing the tube 10,or by pushing it toward the bone graft exit of the tube to push bonegraft out of the tube. The centralizing collar 24 may also facilitatethe packing of the bone graft within the hollow tube 10 and within themedullary canal. In the tube 10, bone graft can be packed against thecentralizing collar 24. In the medullary canal, after the tube 10 iswithdrawn, additional bone graft may be placed into the proximal femoralmedullary canal by the surgeon's fingers, and the plunger 20 can be usedto facilitate the packing of the additional bone graft. By alternatelylifting the plunger 20 out of the canal and inserting it back into thecanal to impact the bone graft, the collar 24 further packs theadditional bone graft in the proximal area.

Of course, various structures or devices could be used to center orotherwise position the plunger 20 or to ensure that the bone graft istransferred to the canal upon the withdrawal of the hollow tube 10. See,for example, the plunger shown in FIGS. 6A-6C and 10, which showpositioning structures only at the proximal end of the plungers.However, the use of a centralizing cap 22 and a centralizing collar 24,separately situated, may be effective in reducing any toggle of theplunger 20 within the tube 10 and thus to maintain the plunger 20 withinthe desired position.

The centralizing cap 22 and the centralizing collar 24 include grooves22a and 24a, respectively, for the release of air during the surgicalprocedure. This will facilitate the use of the plunger 20 while packingthe tube/plunger assembly outside of the bone and while impacting theplunger 20 to further pack the bone graft material within the medullarycanal.

The plunger 20 includes a rod portion 21 below the centralizing collar24, which is to be inserted into the medullary canal. Rod portion 21 canbe of any suitable size (length or thickness) and shape. In thepreferred embodiment, the rod portion 21 is cylindrical in shape formore than half of the rod portion 21, the lower approximately one thirdbeing slightly tapered, as shown in FIG. 2. In fact, the rod portion 21of the plunger 20 could emulate at least the distal portion of theimplant stem which will finally be implanted in the canal, or it couldemulate the entire stem of an implant. The degree of similarity betweenthe rod portion 21 and the implant might depend on the joint beingreplaced, surgeon preference and other factors.

In the preferred embodiment, the centralizing cap 22 and collar 24"bear" against the interior surface of the hollow tube in that thesestructures were undersized with regard to the interior diameter of thehollow tube 10. Any tolerance between the outer diameter of apositioning device and the inner diameter of the hollow tube 10 thatfacilitates the desired positioning function (and graft retainingfunction, if desirable) is acceptable. However, free sliding movement ofsuch a positioning or graft retaining device within the hollow tube ispreferable. Of course, the above relates to the preferred embodiment ofthe present invention in which the positioning and/or graft retainingdevice is inside the hollow tube 10. Also, since the centralizing cap 22and collar 24 in the preferred embodiment are sized to fit within thehollow tube 10, an instrument kit which includes several differentlysized tubes 10 must also include a number of plungers 20 whichcorrespond in size to the tubes 10.

FIG. 3 illustrates a modular plunger, generally designated as 120 andhaving a rod portion 121, which is separate from an upper portion 121a.(Alternatively, the rod portion 121 can be integral with the upperportion 121a to form yet a different modular plunger.) The rod portion121 and upper portion 121a can be of different sizes, and an instrumentkit may include several different sizes (widths and lengths) and shapesso that the rod portion 121 and upper portion 121a can be matchedpreoperatively or intraoperatively. The plunger 120 is adapted toreceive, via a threaded connection or otherwise, any one of a pluralityof centralizing caps 122 and centralizing collars 124. The centralizingcaps 122 and centralizing collars 124 would be of different sizes toaccommodate the differently sized tubes 10 within an instrument kit.Thus, one modular plunger 120 and several caps 122 and collars 124 wouldbe required within a set of instruments. The appropriately sizedcentralizing caps 122 and centralizing collars 124 would be selectedbased on the selection of the tube 10. Of course, this type ofmodularity is not limited to centralizing caps and collars, butpositioning devices of any type which might be used in connection with aplunger.

FIG. 4 shows a hollow bone graft packer 26 which is adapted to betelescopically inserted into the hollow intramedullary tube 10 while theplunger 20 is in place within the hollow intramedullary tube 10. Thebone graft packer 26 also includes grooves 26a for permitting air toescape during use, and further includes a knurled handle 26b at one end.As shown in FIG. 5, the bone graft packer 26 facilitates the packing ofbone graft within the tube/plunger assembly. The bone graft packer 26may also include a device (not shown) arranged at the packing end toenlarge the end of the packer 26 and thus facilitate packing. Such adevice might be removably attached to the end of the packer 26, perhapsby threads. The device would provide a greater packing area to pack thebone graft in the donut-shaped area around the plunger 20 and within thetube 10.

As shown in FIG. 5, the bone graft material, generally designated as 50,is packed within the tube 10 by the bone graft packer 26 such that thebone graft material 50 surrounds the rod portion 21 of plunger 20. Here,the bone graft material 50 is preferably packed as tightly as possiblewithin the tube 10. The initial packing step may include inverting thetube/plunger assembly and pushing it into a container of bone graft tobegin filling the tube with bone graft.

While FIG. 5 illustrates the packing of the bone graft within the tube10 while the plunger 20 is within the tube 10, the tube 10 could bepartially or fully packed prior to insertion of the plunger 20. Once theplunger 20 is inserted into the tube 10, further compaction of the bonegraft material 50 could be accomplished through the use of the bonegraft packer 26.

FIGS. 6A-6F illustrate the delivery of the bone graft material 50 to thefemoral medullary canal in accordance with an embodiment of the presentinvention. However, prior to the steps shown in FIG. 6A, thetube/plunger assembly must be prepared (e.g., as described above withrespect to FIG, 5), and the medullary canal of the distal femur must beprepared. A particular advantage of the preferred embodiment of thepresent invention resides in the fact that the tube/plunger assembly canbe packed and prepared for use prior to even exposing the patient'sbone.

The preparation of the distal femoral medullary canal may include therevision or removal of a previously implanted hip implant, distal plug(if any) and any associated cements or other materials. An appropriatelysized reamer, selected preoperatively and/or intraoperatively, may beused (if necessary) to clean the medullary canal to a size correspondingto the selected hollow intramedullary tube 10. The material cleaned outmay include cement, marrow and/or bone, depending upon surgeonpreference, the application, etc. A distal plug 40 may then be insertedinto the medullary canal at a location which is selected preoperativelyand/or intraoperatively. The next preferable step in the bone graftdelivery technique in accordance with the present invention is to packan appropriate amount, e.g., 1-2 inches, of bone graft material 50against the distal plug 40 (which can be of any suitable material orstructure). This can be accomplished with any suitable instrument whichfits into the medullary canal. The medullary canal is now prepared forreceiving the tube/plunger assembly.

As shown in FIG. 6A, the tube/plunger assembly is inserted into theprepared femoral medullary canal against the distal plug 40 and/or anybone graft material which was previously packed against the distal plug40. It is noted that the plunger 20 illustrated in FIG. 6A has a rodportion 21 which is conical in shape as opposed to cylindrical with adistal taper (as in FIGS. 2 & 3). Also, the plunger 20 in FIG. 6Aincludes a cap or thin flange 22 at its proximal end to facilitate thepositioning, in this case centering, of the plunger 20 within the tube10.

FIG. 6B illustrates the delivery of the bone graft material 50 to themedullary canal by reason of the withdrawal of the tube 10 from themedullary canal, simultaneously with the application of pressure, fromthe proximal towards the distal end, of the plunger 20. The plunger 20may be held in one place (by such pressure) while the tube 10 is beingwithdrawn from the medullary canal, or further pressure can be appliedto push the plunger 20 into the medullary canal at the same time thetube 10 is being withdrawn. Pressure can be applied against the plunger20 by the rod 39 of the extractor 36 (shown in FIG. 7B and describedbelow), or with a rod driver (not shown), which may be held against theplunger 20 by the surgeon while withdrawing the tube 10. In some cases,there may be some incidental proximal movement of the plunger, but thisis not preferable (even though the application of further pressure tothe plunger will move the plunger into the desired position).

During withdrawal of the tube 10, the centralizing collar 24 (shown inFIG. 2) prevents at least any appreciable amount of bone graft 50 frommoving out of the canal with the tube 10, and forces the bone graft 50distally so that it is transferred into the canal. As the tube 10 iswithdrawn from the medullary canal, the space occupied by its thin walls10A is filled with the bone graft material 50. Preferably, it is thenpacked more tightly by the plunger 20.

Following the withdrawal of the tube 10, the plunger 20 is preferablyforced further into the medullary canal to further compact the bonegraft material 50. This can be accomplished in any suitable manner,including the impaction of the top of the plunger 20. FIG. 6C shows thefurther compaction of the bone graft material. Once the desired degreeof bone graft compaction has been attained, the plunger 20 is removedfrom the medullary canal. The length of the plunger 20 between thecentralizing collar 24 and cap 22, and the cap 22 itself, facilitate theremoval of the plunger 20. This leaves a plunger cavity 28 within thepacked bone graft material, as shown in FIG. 6D.

The medullary canal is now prepared for trial packing and reduction.Preferably, the packing is accomplished through the sequential use of aset of trial implants, ranging from small to larger. As is well known inthe field, trial implants often have a shape which is the same orsimilar to the final implant. FIG. 6E shows a trial hip implant 30,which represents any trial of a set of differently sized trial hipimplants. While the bone graft 50 has been well compacted through theuse of the plunger 20, trial implant 30 and subsequent trial implantsare used within the plunger cavity 28 to shape the bone graft 50 andthus form a cavity which matches the final implant, as shown in FIG. 6E.The sequential use of successively larger trial implants facilitates theefficient shaping of the bone graft 50. The last trial implant used maymatch the size, as well as the shape, of the final implant, or if thefinal implant is to be cemented, the last trial implant used may be of asize larger than the size of the final implant. This will leavesufficient room for a cement mantle 32 within the cavity formed in thebone graft 50. During the use of the trial implants 30 to shape theplunger cavity 28, it is preferable to finger-pack or otherwise packbone graft 50 in the proximal area of the femoral medullary canal sothat the shape of the proximal portion of the trial implant 30, and thusthe final implant 35, is adequately formed in the canal.

FIG. 6F shows the implantation of the final implant 35. As is shown inFIG. 6F, a cement mantle space 32 is provided between the bone graft 50and the implant 35.

The present invention relates not only to the delivery of bone graftmaterial to the medullary canal of a bone, but also relates to thedelivery of bone graft material to any portion of a bone which requiresbone graft material. Thus, for example, the technique contemplatesdelivery to a window cut in a bone, where access to such window for bonegrafting is difficult to obtain because of muscle tissue, etc. In otherwords, the window in the bone may not be fully exposed, such that thehollow tube may be helpful in selectively and controllably placing bonegraft material in or adjacent to such window. The present invention alsocontemplates the delivery of bone graft material with or without the useof a plunger to form a cavity in delivered bone graft material. Thus,the bone graft material can simply be delivered to an area via thehollow tube and without the plunger.

FIG. 7A shows a tube extractor 36, which is quite similar to a caulk gunused to dispel adhesive from an adhesive tube. Specifically, forpurposes of this invention, modifications were made to a cement injectorsold by Stryker Corporation of Kalamazoo, Mich. under catalog #206-600.The modified cement injector or tube extractor 36 can be used tofacilitate the withdrawal of the tube 10 during the delivery of the bonegraft 50 into the medullary canal. The tube extractor 36 includes aslotted retaining sleeve 38 which has a slot 38A for receiving theretaining flange 18 of the extraction cap 12 (shown in FIG. 7B), therebyconnecting the extractor 36 to the extraction cap 12 and thus the tube10. The slot 38A and the slotted retaining sleeve 38 have been in otherinstances used to hold the flange of a container of cement or othermaterial. The extractor 36 includes a rod 39 and a rod collar 39a whichwill bear against the centralizing cap 22 or other structure at the endof the plunger 20. This is shown in the cutaway portion in FIG. 7B. Aswith many caulk guns, the rod 39 includes ratchet teeth 39b whichfacilitate the advancement of the rod 39 when the extractor handle 37 isactuated. However, any other suitable means for advancing the rod 39 canbe used.

FIG. 7B shows the extractor 36 connected to the extraction cap 12 viathe slotted retaining sleeve 38 of the extractor 36 and the groove 16and retaining flange 18 of the extraction cap 12. In FIG. 7B, theextraction cap 12 is connected to the tube 10 against the tube flange14. The plunger 20 is assembled within the tube 10 and is surrounded bythe bone graft 50. The rod collar 39a is shown in the cut-away portionbearing against the centralizing cap 22.

In practice, upon the actuation of the extractor handle 37, the rod 39of extractor 36 will be forced downwardly against the plunger 20.Because the plunger 20 is bearing against either the distal plug 40 orcompacted bone graft 50 which is against the distal plug 40, the tube 10will move distally out of the medullary canal, leaving the plunger 20 inplace (or forcing it further downwardly). While the tube 10 can bewithdrawn in any suitable manner, the use of the extractor 36 may bequite helpful in controllably removing the tube 10.

While centralizing cap 22 and collar 24 serve the purpose, among others,of centralizing the rod portion 21 of plunger 20 during initial assemblyof the tube 10 and plunger 20, it is possible that the centralizedposition might be moved after that initial assembly. This may occurduring the insertion and packing of the bone graft material 50 aroundthe rod portion 21 within the tube 10. To ensure that the packing of thebone graft material 50 within the tube/plunger assembly does not shiftthe rod portion 21 from its centralized position, adjunct centralizingmeans can be employed- FIG. 8 illustrates the use of two centralizingscrews 52a and 52b, which threadedly engage diametrically opposed holesin the tube 10 and engage the rod portion 21. Together thesecentralizing screws help ensure that the rod portion 21 remains in thecentralized position- The structure of these centralizing screws 52a and52b may be changed to accommodate any position (other than central) ofthe rod portion 21 within the tube 10. In addition, while thecentralizing screws 52a and 52b are disclosed as adjunct positioningmeans, they can be used (as shown or in additional pairs) as primarypositioning means in lieu of cap 22 and collar 24, or just in lieu ofcollar 24 (so that they would work with cap 22).

FIG. 9 illustrates yet another technique for ensuring that the rodportion 21 remain in the centralized position (or any other desirableposition). Here, a centralizing washer 54 (or multiple such washers) maybe used. This washer 54, preferably made out of a plastic material, isinserted over the rod portion 21, and remains in place by aninterference fit. In the preferred embodiment of these washers, radialrelief cuts are made from the central hole, so that the washer can beslid over a tapering rod. Thus, the washer 54 can be further forced ontothe cylindrical portion of the rod portion 21 during the packing of thetube/plunger assembly. The washer 54 will finally rest against thecentralizing collar 24, but in the meantime will have helped ensure thatthe position of the rod portion 21 remains as it was originally set. Thepossibility of the washer 54 being left behind after removal of the tube10 and the plunger 20 has been recognized. Thus, the washer 54 ispreferably biocompatible and detectable by X-ray. It might be such thatthe washer 54 can be left in place with no harm to the subsequentimplantation, or the washer 54 can be extracted prior to finallypreparing the canal. As with the centralizing screws 52a and 52b, thewasher 54 or multiple washers may be useable as the primary positioningmeans, alone or with one or both of cap 22 or collar 24.

FIG. 10 illustrates a particular specialized application using thepresent invention. In FIG. 10, the distal femoral bone includes a void42 on the lateral side of the medullary canal. In this particularapplication, it may be desirable to clean only the area which has beendamaged, while maintaining the strong bone stock in other areas of themedullary canal. Thus, the objective is to selectively place bone graft50 only in void 42. Once the selected area has been cleaned, theselective delivery of bone graft can be accomplished through the use ofa tube 10 and a plunger 20, wherein the plunger 20 has a particularshape and/or orientation with regard to the tube 10 to facilitateselective delivery of the bone graft 50 to the void 42. One way ofaccomplishing this is shown in FIG. 10. In FIG. 10, the bone graft 50 isonly provided on the lateral side of the plunger 20. It is also notedthat the plunger 20 includes flattened areas at least at the top ofproximal portion to facilitate the positioning of the plunger 20 withinthe tube 10. Upon withdrawal of the tube 10, and the further compactionof the bone graft 50, the void 42 is filled or at least partially filledwith the bone graft 50. A further procedure, such as implantation of aprosthetic device, can now be undertaken.

While the foregoing description of figures illustrate the preferredembodiments of the bone graft delivery technique and associatedinstruments in accordance with the present invention, it should beappreciated that certain modifications can be made and are encouraged tobe made without departing from the spirit and scope of the presentinvention which is intended to be captured by the claims set forthimmediately below.

What is claimed is:
 1. A surgical method comprising the steps of:a.providing access to a graft receiving area in a body, which requiresbone graft; b. placing bone graft into a hollow tube having a first endand a second end; c. arranging a plunger at least partially in thehollow tube; d. arranging the hollow tube with bone graft and plungertherein so that the first end of the hollow tube is adjacent to or inthe graft receiving area; e. moving the hollow tube away from the graftreceiving area, such that bone graft exits the first end of the hollowtube and the bone graft and the plunger remain at least partially at thegraft receiving area; and f. removing the plunger from the graftreceiving area after withdrawal of the hollow tube to thereby leave acavity formed at least partially by the bone graft.
 2. The method inclaim 1, further including the step of arranging a graft retainingstructure in the hollow tube at a location remote from the first endthereof to substantially block the hollow tube at the location of theretaining structure, thereby facilitating the exit of bone graft fromthe hollow tube upon the movement of the hollow tube away from the graftreceiving area.
 3. The method in claim 2, wherein the graft retainingstructure is maintained in substantially one position while moving thetube away from the graft retaining area.
 4. A surgical method comprisingthe steps of:a. exposing the medullary canal of a bone; b. placing bonegraft into a hollow tube having a first end and a second end; c.arranging a plunger at least partially in the hollow tube; d. insertingthe first end of the hollow tube into the medullary canal; e.withdrawing the hollow tube from the medullary canal, so that bone graftexits the first end of the hollow tube into the medullary canal; and f.removing the plunger from the medullary canal after withdrawal of thehollow tube to thereby leave a cavity formed at least partially by thebone graft.
 5. The method in claim 4, further including the steps ofpreparing the bone graft in the medullary canal to receive a prosthesisand inserting a prosthesis into the prepared bone graft in the medullarycanal.
 6. The method in claim 4, wherein the step of withdrawing thehollow tube from the medullary canal is accomplished while applyingpressure to the plunger in the direction from the second end to thefirst end of the hollow tube, and further including the step of applyingfurther pressure to the plunger to force the plunger into the medullarycanal and pack the bone graft therein before removing the plunger. 7.The method in claim 6, wherein the step of applying pressure to theplunger includes the application of further pressure to the plungerafter the hollow tube is withdrawn from the medullary canal and suchapplication of further pressure is accomplished by impacting the top ofthe plunger to further pack the bone graft in the medullary canal. 8.The method in claim 4, further including the steps of shaping the bonegraft in the medullary canal with a prosthesis or a trial prosthesishaving a configuration similar to the prosthesis, and positioning theprosthesis into the shaped bone graft in the medullary canal.
 9. Themethod in claim 8, including the step of compacting the bone graftmaterial in the medullary canal with at least two successively largertrial prostheses to progressively shape the bone graft.
 10. The methodin claim 9, including the step of packing additional bone graft in themedullary canal adjacent the exposed end of the medullary canal as suchadditional bone graft is needed during the step of shaping the bonegraft material in the medullary canal with at least two successivelylarger trial prostheses.
 11. The method in claim 9, including the stepof providing a prosthesis for implantation in the medullary canal, andwherein the largest trial prosthesis used to shape the bone graft in themedullary canal is of a size larger than the prosthesis, thereby leavingspace for a cement mantle.
 12. The method in claim 11, including thesteps of injecting cement into the medullary canal and inserting aprosthesis into the medullary canal.
 13. The method in claim 4, whereinthe step of providing a plunger further comprises providing a plungerhaving a graft retaining portion so that when the plunger is arranged inthe hollow tube, the graft retaining portion of the plunger willsubstantially block the second end of the hollow tube, therebyfacilitating the exit of the bone graft from the first end of the hollowtube into the medullary canal during withdrawal of the hollow tube. 14.The method in claim 13, wherein the step of providing a plunger furthercomprises providing a plunger having an elongate rod portion and whereinthe graft retaining portion is a flange which is larger in cross-sectionthan the elongate rod portion.
 15. The method in claim 14, wherein thestep of providing a plunger further comprises providing a plungerwherein the flange is so constructed and arranged that the rod portionof the plunger is substantially maintained in the arranged position withrespect to the hollow tube.
 16. The method in claim 15, wherein the stepof providing a plunger further comprises providing a plunger wherein theplunger has first and second ends corresponding to the first and secondends of the hollow tube, and wherein the flange is a cap on the secondend of the plunger.
 17. The method in claim 13, wherein the step ofproviding a plunger further comprises providing a plunger wherein thegraft retaining portion is a flange which bears against the interiorsurface of the hollow tube.
 18. The method in claim 13, wherein the stepof providing a plunger further comprises providing a plunger wherein thegraft retaining portion is also a positioning device for maintaining theplunger in a desirable position with respect to the hollow tube.
 19. Themethod in claim 18, wherein the step of providing a plunger furthercomprises providing a plunger having an elongate rod portion and havinga cap on the second end of the plunger, the cap having an outer surfacewhich bears against the interior surface of the hollow tube, whereby thecap together with the positioning device maintains the elongate rodportion of the plunger in a desirable position with respect to thehollow tube.
 20. The method in claim 19, wherein the step of providing aplunger further comprises providing a plunger wherein the graftretaining portion includes a collar positioned medially on the plungerabove the elongate rod portion, the collar having an outer surface whichbears against the interior surface of the hollow tube.
 21. The method inclaim 20, wherein the step of providing a plunger further comprisesproviding a plunger wherein the cap and the collar are removeable fromthe plunger and are selectable from a plurality of differently sizedcaps and collars.
 22. The method in claim 21, further including the stepof using an additional positioning device below the collar.
 23. Themethod in claim 22, wherein the step of using an additional positioningdevice further comprises using an additional positioning device whereinthe additional positioning device comprises screws adapted to bethreaded through the hollow tube to engage the rod portion.
 24. Themethod in claim 22, wherein the step of using an additional positioningdevice further comprises using an additional positioning device whereinthe additional positioning device is a washer disposed around the rodportion by an interference fit and slideable along the rod potion duringthe insertion of the bone graft into the tube.
 25. The method in claim4, wherein the step of providing a plunger further comprises providing aplunger having an elongate rod portion and a positioning deviceassociated with the hollow tube for maintaining the rod portion of theplunger in a desirable position with respect to the hollow tube.
 26. Themethod in claim 4, including the step of removing material from aportion of the medullary canal by reaming the canal to a size and shapecorresponding to the exterior size and shape of the hollow tube tocreate an elongate cavity of a predetermined size and shape forinsertion of the hollow tube.
 27. The method in claim 4, wherein thebone graft is placed into the hollow tube after the plunger is arrangedtherein.
 28. The method in claim 27, further including the step ofpacking bone graft into the hollow tube around the rod portion of theplunger with an at least partially hollow bone graft packer by arrangingthe bone graft packer around the plunger and inside of the hollow tubeand forcing the bone graft into the hollow tube.
 29. The method in claim4, wherein the step of providing a plunger further comprises providing aplunger having an elongate rod portion which is at least partiallytapered from large to small from the second end to the first end of thehollow tube.
 30. The method in claim 4, including the step ofpositioning a prosthesis in the bone graft in the medullary canal, andwherein the step of providing a plunger further comprises providing aplunger having an elongate rod portion which has a configuration whichis similar to at least a portion of the prosthesis configuration. 31.The method in claim 4, further including the steps of injecting cementinto the medullary canal and inserting a prosthesis into the medullarycanal.
 32. The method in claim 4, further including the step of removingmaterial from the medullary canal to form a tube-receiving cavity havinga size and shape corresponding to the size and shape of the hollow tube.33. The method in claim 4, including the step of preoperatively orintraoperatively selecting an appropriately sized reamer from a set ofdifferently sized reamers, the selected reamer to correspond in sizewith the hollow tube, and further including the step of reaming themedullary canal to prepare the medullary canal for receiving theselected hollow tube.
 34. The method in claim 4, wherein the bone graftis disposed in only a portion of the hollow tube such that upon thewithdrawal of the hollow tube from the medullary canal, the bone graftis delivered to a selected area of the medullary canal.
 35. The methodin claim 4, including the step of inserting a plug in the medullarycanal and packing bone graft in the medullary canal against the plug.36. The method in claim 4, including the step of removing a previouslyimplanted prosthesis and/or any cement associated with such previouslyimplanted prosthesis, and otherwise preparing the medullary canal forreceiving the hollow tube and plunger.
 37. The method in claim 4,further including the step of arranging a graft retaining structure inthe hollow tube at a location remote from the first end thereof tosubstantially block the hollow tube at the location of the retainingstructure, thereby facilitating the exit of bone graft from the hollowtube upon the movement of the hollow tube way from the medullary canal.38. Surgical instruments comprising a hollow tube having a first end anda second end, said hollow tube being constructed so that it can receivebone graft to be delivered to a graft receiving area of a body so thatsaid first end can be arranged at least adjacent to the graft receivingarea and further so that the bone graft can be delivered from said firstend of said hollow tube to the graft receiving area of a body uponmovement of said hollow tube in a direction from said first end to saidsecond end, and a plunger having a first end and a second end, saidplunger being adapted for insertion at least partially within saidhollow tube, whereby at least a portion of the first end of said plungeris spaced from the wall of said hollow tube when therein, so as tocreate a space for bone graft, said plunger being removable from thefirst end of the hollow tube.
 39. The instruments in claim 38, furtherincluding a graft retaining structure for arrangement in the hollow tubeat a location remote from the first end in order to substantially blockthe hollow tube at that location and to thereby facilitate the exit ofbone graft from the hollow tube during movement of the hollow tube awayfrom the graft receiving area.
 40. The instruments in claim 38, whereinsaid hollow tube is adapted to be inserted into a medullary canal, andwherein said plunger includes an elongate rod portion extending betweensaid first and second ends thereof.
 41. The instruments in claim 40,wherein said plunger includes a graft retaining portion whichsubstantially blocks an end of the hollow tube to facilitate the exit ofbone graft from the hollow tube into the medullary canal duringwithdrawal of the hollow tube.
 42. The instruments in claim 41, whereinthe graft retaining portion is also a positioning device for maintainingthe rod portion of the plunger in the arranged position with respect tothe hollow tube.
 43. The instruments in claim 42, further including acap on said second end of the plunger, the cap having an outer surfacewhich bears against the interior surface of the hollow tube, the captogether with the graft retaining portion substantially maintain the rodportion in the arranged position with respect to the hollow tube. 44.The instruments in claim 42, wherein the hollow tube has an interiorsurface, and wherein the graft retaining portion includes a collarpositioned medially on the plunger above the elongate rod portion, thecollar having an outer surface which bears against the interior surfaceof the hollow tube.
 45. The instruments in claim 44, wherein the cap andthe collar are removeable from the plunger and are selectable from aplurality of differently sized caps and collars.
 46. The instruments inclaim 40, wherein said plunger includes a positioning device associatedwith said hollow tube for maintaining the rod portion of the plunger inthe arranged position with respect to the hollow tube.
 47. Theinstruments in claim 46, further including an additional positioningdevice below the collar.
 48. The instruments in claim 47, wherein theadditional positioning device comprises screws adapted to be threadedthrough the hollow tube to engage the rod portion.
 49. The instrumentsin claim 47, wherein the additional positioning device is a washerdisposed around the rod portion by an interference fit and slideablealong the rod portion during the insertion of the bone graft into thetube.
 50. The instruments in claim 46, wherein said positioning deviceis a cap on an end of said plunger and a collar located medially on saidplunger.
 51. The instruments in claim 46, wherein at least a portion ofsaid elongate rod portion of said plunger is tapered.
 52. Theinstruments in claim 40, wherein at least a portion of said elongate rodportion of said plunger is tapered.
 53. The instruments in claim 52,wherein said tapered portion of said elongate rod portion matches atleast a portion of a prosthetic device to be implanted in the medullarycanal.
 54. The instruments in claim 40, wherein at least a portion ofsaid elongate rod portion of said plunger is of a shape which is similarto the shape of a prosthetic device to be implanted in the medullarycanal.
 55. The instruments in claim 40, further including a bone graftpacker, at least a portion of said bone graft packer being hollow, saidbone graft packer being sized to fit telescopically within said hollowtube about said plunger to pack bone graft into the hollow tube prior tothe insertion of the hollow tube/plunger assembly into a medullarycanal.
 56. The instruments in claim 55, further including an extractioncap attached to an end of said hollow tube to facilitate the withdrawalof the hollow tube from the medullary canal.
 57. The instruments inclaim 56, further including an extractor to facilitate the withdrawal ofthe hollow tube from a medullary canal, said extractor including ahousing, means for connecting said housing to said extraction cap, a rodmoveable within said housing for applying pressure to said plunger uponactuation of the extractor, and actuating means for applying pressure tosaid plunger, said extractor being constructed and arranged so that uponthe actuation of said extractor, said rod applies pressure against saidplunger, and said housing, together with said extraction cap and hollowtube, move away from said plunger to thereby withdraw the hollow tubefrom the medullary canal.
 58. The instruments in claim 38, furtherincluding a bone graft packer, at least a portion of said bone graftpacker being hollow, said bone graft packer being sized to fittelescopically within said hollow tube to pack bone graft into thehollow tube.
 59. The instruments in claim 38, wherein the hollow tube ismade of a disposable material, such that it can be disposed of after asingle use.
 60. The instruments in claim 38, further including bonegraft, said bone graft being stored within the hollow tube, the hollowtube and bone graft being capable of being stored together for a periodof time before use in a surgery.
 61. The instruments in claim 60,wherein the hollow tube is made of a disposable material, such that itcan be disposed of after a single use.
 62. Surgical instrumentscomprising a tube sized for placement in an opening made in a body; aplunger sized for arrangement within the tube together with graftmaterial; and an extractor to facilitate the controlled movement of thetube while leaving the plunger, said extractor including a housing, aconnector for connecting the housing to the tube, a stem movable withinsaid housing for applying pressure to the plunger upon actuation of theextractor, and actuating means for applying pressure to the plunger,said stem having an engaging portion sized to engage the plunger in thetube and to permit the tube to be withdrawn from a body, said extractorbeing constructed and arranged so that upon actuation of said extractor,said stem applies pressure against the plunger, and so that saidhousing, together with the connected tube, move away from and areseparated from the plunger.
 63. The instruments in claim 62, whereinsaid extractor is a modified cement injector gun.